A system and a method for on-site drug detection and quantification based on the Spectral Fluorescence Signatures (SFS) technology are disclosed in WO2005111586. The system of this invention consists of an ultraviolet-visible light source, a condenser/filter assembly with filter drive, an excitation monochromator with diffraction grating drive, a reference photo-detector, a cell assembly for liquid, solid and powder samples, an absorption photo-detector, an emission monochromator with diffraction grating drive, and an emission photo-detector. A microcontroller unit is provided for device controlling, data processing, and communication with an external computer via different link types. The detection and quantification of illicit drugs in the analyzed sample are provided by measuring simultaneously the emission spectra of fluorescence at every step of excitation wavelength in selected and fixed excitation, emission and absorption spectral windows in a way to cover specific excitation, emission fluorescence and absorption spectral ranges of all major drugs, adulterants and diluents; and processing the united result in a computer system based on combination of preliminary prepared spectral library and specialized software consisting of identification, interaction verification and automatic calibration modules.
A system and a method of analysis of illicit drug samples disclosed in WO2005111586 are limited in detection by the concentration of the substances of interest, in particular Heroin. Due to low fluorescence efficiency of Heroin and interfering influence of adulterants and diluents, the specific patterns in SFS structure caused by said substances at certain concentration of Heroin are not recognized by the expert system.
WO 2008040386 discloses a method for on-site drug detection in illicit drug samples enabling preferably Cocaine drug detection in street samples containing in addition to Cocaine also adulterants and/or diluents. The method provides preparing of the liquid street sample, taking of an aliquot of said sample, its analysis with help of SFS (Spectral Fluorescence Signatures) technology, fixing the result of analysis as a reference value, the subsequent acidification of the liquid sample, taking an aliquot of the acidified liquid sample and its analysis with help of SFS technology, fixing the result of analysis and comparing said result with the reference value. The result of comparison enables to differentiate between Cocaine Base and Cocaine hydrochloride in the street sample. On the essence, the subject invention uses an additional chemical reaction for modifying the sample before performing the second measurement. This chemical reaction enables to raise the intensity of the sample for analysis with SFS technology by way of converting Cocaine Base to Cocaine hydrochloride.
The above method as such cannot be used for detection of Heroin in illicit drug samples because the simple acidification of a sample and comparison the results of the measurement of the sample before and after acidification does not grant the reliable results due to the specific chemical qualities of Heroin and existence of adulterants and/or diluents in the sample.
At the same time, the need for a technical solution, which increases the sensitivity and selectivity of on-site analysis related to Heroin and Morphine detection in a mixture with cutting agents (adulterants and diluents) is mandated by the legal requirements in illicit drug distribution prevention. The current sentencing structure for Heroin offences (United States Sentencing Commission. Guidelines Manual. 2006) in the Schedule I of the referenced document provides for the less than 5 g of Heroin the same sentences as for about 25 g of Cocaine. Liability for seized 1 g of Heroin is equal according to this document to 1 kg of Marijuana (Marihuana). Sentencing structure for Morphine offences has been put in the Schedule II. Liability for seized 1 g of Morphine is equal according to the same document to 500 g of Marijuana (Marihuana). The cited documents illustrate necessity to provide reliable and selective detection of Heroin and Morphine to fight effectively against this illegal drugs trafficking and abuse.